It's called "Motorist's Choice." But the new emissions testing program for Houston may not offer much of a choice after all. And it won't do much for cleaning the city's air, either.

Regardless of the motives of participants, one of the aspects of Motorist's Choice that will make it more palatable to the public, says Stieb, is that motorists can select from among, say, the 500 plus test sites that Rainey estimates will be available, instead of the mere 27 Tejas testing stations under the I/M 240 plan. From the standpoint of "choice," however, the net result of the new program probably will be a wash: more choices for emissions testing, fewer choices for safety inspections.

One of the reasons the EPA supports I/M 240 programs has nothing to do with the technology of the test, though it does provide the most conclusive data. I/M 240 is a centralized, test-only program, meaning that sites conduct emissions tests, and that's it. Needed repairs must be done by a motorist's regular mechanic.

That may be inconvenient for owners whose cars fail the breathalyzer, since after the repair they have to go back for a retest; thus, the irritating "ping-pong" effect cited by Stieb. But it's a lot less problematic than being charged a couple of hundred dollars for an unneeded repair, only one reason why the EPA has bad things to say about "test-and-repair" programs like Motorist's Choice.

Tim Hogan believes that test-and-repair practice will pose some interesting ethical dilemmas. "The incentive to fail somebody is going to be really high," he says. Since the return on the test itself is marginal, Hogan says, "[participants] are gonna have to get some repairs out of it to pay for the equipment."

The flip side of the fraud issue favors the motorist, but at the expense of cleaner air. As has been well documented elsewhere, station owners are inclined to pass the cars of their regular customers, no matter how foul the tailpipe. And the lower-tech test, which involves sticking a sensor in a car's tailpipe instead of running the vehicle at variable speeds on a treadmill, is much easier to fudge.

Even the TNRCC recognized the problem inherent in a decentralized test-and-repair program.

"It's obvious that having testing and repair at the same place creates a conflict of interest," Richard Flannery, an administrator in the agency's Houston office, said in 1994.

No matter how dutiful a state's attempt to police its program, nothing seems to work. Numerous studies in New York, California and other states that have decentralized emissions testing all lead to the conclusion published in the "EPA I/M Briefing Book," the agency's thick primer: "Test-and-repair is not effective at reducing vehicle emissions."

That's why until recently the EPA only gave states with test-and-repair programs half credit for the emissions reductions shown in their computer models. In other words, if Motorist's Choice resulted in a reduction of 14 tons of ozone-causing pollutants in Houston per day, Texas would only have been able to claim credit for seven tons toward its mandated reduction goal.

Despite the evidence, Texas and other states with pollution problems put an end to that bit of government meddling. With Bush and TNRCC officials joining the national inquisition of the EPA, the agency suddenly found new flexibility: Texas could claim full credit for its program, as long as the state could demonstrate its effectiveness and back it with an 18-month review.

That pleases John Stieb, who says assuming shops will engage in dubious practices is unfair. And he challenges the idea that anyone would take advantage of the rules. "We believe in innocent until proven guilty," he says. "We believe that the [service providers] are honest."

Stieb is confident that when the data is in, Texas will pass the big emissions test. "What we intend to do is demonstrate to the EPA the integrity of the program," he says.

That may not be so easy. In its effort to make Motorist's Choice as painless as possible, the state has cut a few corners. Adequately enforcing a test-and-repair program, for example, requires a heavy investment of time and labor. California spends roughly $7 per vehicle on its oversight program, which would mean $21 million annually to monitor the Harris County end of Motorist's Choice. But Texas is planning no such investment, according to Stieb. In fact, he says, oversight of the new program won't cost much more than supervision of the old one would have, perhaps about $5 million.

But again, it wasn't long ago that the agency was telling a different story. Arguing for I/M 240 in 1994, TNRCC's Richard Flannery said, "Going decentralized would have logarithmically increased that state's oversight costs."

Stieb now says that Texas will realize significant savings by putting the Department of Public Safety, which enforces the safety-inspection program, in charge of emissions oversight. But EPA environmental protection specialist David Sosnowski is dubious. "Logic seems to disagree with that," he says, reeling off a list of flaws. How, for example, can a covert auditing of 500 stations, which requires pre-setting cars to pass and fail and running them through, as well as other checks and balances, cost the same as supervision of the 27 Tejas sites?

That's not the only iffy part of the plan. Motorists who fail the test and don't get repaired, or those who don't bother to get the test at all, will find their registration renewal denied when they show up at the window. That is, if the Legislature approves tying the test to registration denial, which was expressly prohibited by a bill passed last session.